Aortic arch prosthetic graft

ABSTRACT

An implantable tubular textile prosthesis particularly useful in branched end-to-side anastomoses is provided. The prosthesis includes a first portion including an elongate tubular main wall which defines a fluid passageway therethrough, and a second portion including a tubular branch wall which extends laterally from the tubular main wall and which defines a fluid passageway therethrough. The tubular branch wall includes an elongate tubular extent and a contiguous flared tubular extent. The tubular branch wall is secured to the tubular main wall at the flared tubular extent to establish fluid communication between the passageways of the tubular main wall and the tubular branch wall. The flared tubular extent includes a gradual increase in diameter with respect to the tubular branch extent to provide a seamless and substantially fluid-tight transition between the tubular main wall and the tubular branch wall along the flared tubular extent.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.09/758,602, filed Jan. 11, 2001, now U.S. Pat. No. 6,478,817 which is acontinuation of U.S. patent application Ser. No. 08/923,298, filed Sep.4, 1997, now U.S. Pat. No. 6,187,033, all of which are incorporatedherein by reference.

FIELD OF THE INVENTION

The present invention is directed generally to a vascular prosthesiswhich is useful in repair or replacement of a branched section of ablood vessel. More particularly, the present invention provides atextile vascular graft which is substantially fluid-tight and which isparticularly useful in branched end-to-side anastomoses.

BACKGROUND OF THE INVENTION

The use of tubular textile fabrics for soft-tissue implantableprostheses is well known in the repair or replacement of damaged ordiseased lumens in the body. For example, tubular devices or conduitsare used to repair lumens such as in the esophagus and colon areas, and,in particular, prostheses are used in the vascular system to repair,buttress or replace a weakened section of the vessel. Such conduits aregenerally affixed in a specified location in the vessel by means ofsutures, stents, hooks or other mechanisms which serve to secure thedevice in place.

Synthetic vascular grafts for the repair or replacement of blood vesselshave taken a wide variety of configurations and shapes. The most commontype of vascular graft is that manufactured in a generally tubular formextending along a longitudinal axis. Such tubular vascular grafts areparticularly well suited for use in end-to-end anastomoses, i.e., wherethe damaged portion of the blood vessel is dissected and the ends of thetubular graft are connected to the cut ends of the blood vessel to spanthe dissected portion. These tubular grafts may also be used inend-to-side anastomoses, i.e., where the end of a graft tube istypically attached to the side of a blood vessel. Such tubular vasculargrafts are also useful in percutaneous applications, where the graft isinserted percutaneously and is positioned to span a damaged or diseasedportion of a blood vessel without dissection.

Various designs have been proposed in order to provide for propersuturing and proper internal blood flow with end-to-end as well asend-to-side vascular grafts. For example, U.S. Pat. No. 5,156,619discloses a flanged end-to-side vascular graft which is provided in theform of a tubular vascular graft having a flared end portion. Such agraft is cannibalized, i.e., cut, from a conventional bifurcated graftstructure which includes a main tubular section and two smaller branchedtubular sections. The bifurcated graft is cut along an arcuate segmentat the bifurcated arch between the bifurcated tubular sections and alongthe wall of the main tubular section, to provide a single tubular graftwith a flanged end formed from the arcuate cut. The flanged end,however, typically requires stitching along the flanged portion, sincebifurcated textile grafts of the prior art typically require suturing atthe bifurcated portion in order to be blood-tight. Further, as theflanged graft in the '619 patent is constructed of only a single tubewith a flange at one end, it is designed to be attached to an end of ablood vessel, and is not suitable for repair or replacement of abranched section of a blood vessel. Still further, the graft disclosedin the '619 patent is designed to extend from the blood vessel at agradually sloping angle, and would not be appropriate for applicationswhere an end-to-side graft is required which incorporates a branchextending substantially perpendicular to a main tubular section.

Occasionally, it is necessary to provide an end-to-side vascular graftin which the side branch portion extends substantially perpendicularfrom the main portion to replace a portion of a blood vessel or to bepositioned within a portion of a vessel which splits into one or morebranch vessels. In order to overcome the deficiencies of earlierend-to-side grafts which do not include a generally perpendicularextending branch, true end-to-side vascular grafts have been constructedwith branch portions which extend generally perpendicular to the maintubular section. Such end-to-side vascular grafts have typically beenconstructed by suturing one tubular vascular graft to the side of asecond tubular vascular graft. Such end-to-side vascular grafts areused, for example, to repair or replace a damaged or diseased portion ofthe aorta. In such procedures, an aortic vascular prosthesis whichincludes a main aortic trunk portion and arterial branch portionsextending generally perpendicular to the main aortic trunk portion forthe left and right carotid arteries and the subclavian artery isparticularly well suited. In order to provide an aortic vascularprosthesis with three branches, a surgeon will typically suture threeseparate straight tubular vascular grafts to the side of a largertubular graft. Such suturing, however, usually occurs immediately priorto or during a procedure, is labor intensive and requires extreme skilland precision in suturing, thereby introducing the potential for humanerror.

Prior art end-to-side vascular grafts such as the aforementioned aorticvascular prostheses have not been completely successful. In particular,the attachment of one tubular graft to the side of another tubular graftresults in a sharp transition, typically with an immediate transition of90° from the main tubular section to the branched tubular section.Additionally, such attachment results in suturing or stitching directlyat the point of transition between the main tubular section and thebranched tubular section. Such sharp transitioning and suturing at thistransition result in poor blood flow through the transitional portion,and can lead to an undesirable thrombosis at the transition.

Alternatively, custom-made aortic vascular prostheses can beconstructed. While these custom-made structures may overcome some of theaforementioned deficiencies, they are extremely expensive andtime-consuming to fabricate.

Accordingly, there is a need for a vascular graft which is useful inrepair or replacement of a branched section of a blood vessel which issubstantially blood-tight and includes a gradual transition from themain lumen to the branched lumen, and which does not include anysuturing directly at the lumen transition.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a vascular graftwhich is useful in the repair or replacement of a blood vessel.

It is a further object of the present invention to provide a branchedvascular graft which is useful in an end-to-side anastomosis.

It is a further object to provide an end-to-side vascular graft whichincludes a gradual transition from the main portion to the branchedportion.

It is yet a further object of the present invention to provide abranched aortic arch vascular graft which is useful in end-to-sideanastomoses involving the aorta and arterial branches of the left andright carotid arteries and the subclavian artery.

In the efficient attainment of these and other objects, the presentinvention provides an implantable tubular textile prosthesis whichincludes a first portion including an elongate tubular main wall whichdefines a fluid passageway therethrough, and a second portion includinga tubular branch wall which extends laterally from the tubular main walland which defines a fluid passageway therethrough. The tubular branchwall includes an elongate tubular extent and a contiguous flared tubularextent. The tubular branch wall is secured to the tubular main wall atthe flared tubular extent to establish fluid communication between thepassageways of the tubular main wall and the tubular branch wall. Theflared tubular extent incorporates a gradual increase in diameter withrespect to the tubular branch extent to provide a seamless andsubstantially fluid-tight transition between the tubular main wall andthe tubular branch wall along the flared tubular extent.

The flared tubular extent may include a textile pattern which has aplurality of warp yarns and fill yarns and incorporates a gradual changein the number of warp yarns with respect to the fill yarns. The gradualchange is preferably defined by a change of no more than 3 warp yarnsfor every 2 fill yarns in the textile pattern.

The prosthesis of the present invention is a textile product, and ispreferably constructed of textile materials such as woven materials,knitted materials, braided materials, and mixtures thereof. The textilematerial may be any known material, for example, polyester,polypropylene, polyethylene, polyurethane, polytetrafluoroethylene andmixtures thereof.

The tubular main wall of the prosthesis may be straight, or, morepreferably, may be arched, for example, by pre-forming into the shape ofan aorta, with the elongate tubular extent extending substantiallyperpendicular from the main tubular wall. The prosthesis may include aplurality of elongate tubular extents at the tubular branch portion, andpreferably includes three elongate tubular extents, for anastomosis withthe left, right and subclavian arteries, respectively. The plurality ofelongate tubular extents may be of equal or different diameters andlengths. In particularly preferred embodiments, the plurality ofelongate tubular extents are spaced along an axis with respect to thetubular main wall, and are circumferentially offset with respect to thetubular main wall. The prosthesis may further include an elongatetubular port extending laterally from the tubular main wall at alocation remote from the tubular branch wall, which is particularlyuseful during implantation procedures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an aortic graft constructed inaccordance with the prior art.

FIG. 2 is a perspective view of a textile vascular graft according tothe present invention.

FIG. 3 is a perspective view of an aortic arch graft constructed inaccordance with the preferred embodiment of the present invention.

FIG. 4 is a perspective view of an aortic arch graft of the presentinvention in an alternate embodiment.

FIG. 5 is a partial cutaway view of a portion of an aortic graftconstructed according to the prior art depicting an internal portion ofthe main wall at the transition to the tubular branches.

FIG. 6 is a partial cutaway view of a portion of an aortic graftconstructed according to the present invention depicting an internalportion of the main wall at the flared transition to the tubular branch.

FIG. 7 is an end view of the aortic graft depicted in FIG. 4.

DETAILED DESCRIPTION OF THE INVENTION

As noted, the present invention is directed to a vascular prosthesiswhich is useful in repair or replacement of a branched section of ablood vessel, and provides a textile vascular graft which issubstantially fluid-tight and which is particularly useful in branchedend-to-side anastomoses.

The prosthesis of the present invention is constructed of a textilematerial. Textile materials, for example textile tubular prostheseswhich are woven, knitted and/or braided, have gained widespread use asimplantable tubular prostheses. In particular, woven or knitted textiletubular prostheses which are manufactured using tubular flat-weavingtechniques are a common implant material for vascular grafts.

In tubular textile manufacturing processes, a variety of yarns areinterlaced to create a tubular product. For example, a set of warp yarnsis used which represents the longitudinal axis of the product beingmanufactured, and a fill yarn is interlaced in a transverse relationbetween the warp yarns. The fill yarn is continuously interlaced acrossthe length of the warp yarns to form a tubular textile structure. Suchmanufacture will be discussed in more detail herein.

With specific reference to FIG. 1, a conventional aortic arch prosthesis10′ of the prior art is shown. Prosthesis 10′ includes generallylongitudinal tubular main portion 20′ including elongate tubular mainwall 21′. Tubular main portion 20′ includes a first open end 22′ and anopposed second open end 24′, and further includes a main lumen 25′extending therethrough. Tubular branches 30 a′, 30 b′ and 30 c′ extendlaterally from tubular main wall 21′ of tubular main portion 20′.Tubular branches 30 a′, 30 b′ and 30 c′ include tubular branch walls 31a′, 31 b′ and 31 c′, respectively, which define branch lumens 35 a′, 35b′ and 35 c′, respectively. Tubular branches 30 a′, 30 b′ and 30 c′ areindividually sutured to tubular main portion 20′ at the intersection ofeach tubular branch wall 31 a′, 31 b′ and 31 c′ with tubular main wall21′ thereof by sutures 15′. As such, a path of fluid communicationbetween main lumen 25′ of tubular main portion 20′ and branch lumens 35a′, 35 b′ and 35 c′ of tubular branches 30 a′, 30 b′ and 30 c′ isestablished, thereby providing a passageway for blood flow therethrough.The sutures, however, are positioned directly at the transition of maintubular lumen 25′ with branch lumens 35 a′, 35 b′ and 35 c′.

Referring now to FIG. 2, a branched prosthesis 10 according to thepresent invention is shown. Prosthesis 10 includes generallylongitudinal tubular main portion 20 including elongate tubular mainwall 21. Tubular main portion 20 further includes first open end 22 andopposed open end 24, with a main lumen 25 extending therethrough.Tubular main portion 20 is preferably of a generally constant internaldiameter along the length thereof. In preferred embodiments, tubularmain portion 20 is constructed so as to repair or replace a damagedportion of an aorta in an adult mammal. Accordingly, tubular mainportion 20 includes an internal diameter appropriately sized for suchuse, for example, approximately 26 millimeters. Alternatively, tubularmain portion 20 may be constructed with an internal diameter whichvaries along the length thereof.

Tubular main portion 20 may be constructed of any known textilematerial. For example, tubular main portion 20 may be a textile materialselected from the group consisting of woven material, knitted material,braided material, and the like. Preferably, tubular main portion 20 is awoven textile material. Additionally, the textile material may include avelour inner and/or outer surface, for instance, to facilitate tissueingrowth and cell attachment thereto.

While tubular main portion 20 is generally elongate in shape, it may beconfigured into any desirable shape. For example, in the preferred useas an aortic graft, tubular main portion 20 may be arched in shape toresemble the natural arch of the aorta. Such arch may be accomplished byproviding tubular main wall 21 with crimps, as is known in the art.Alternatively, such arch may be provided by incorporating heat-settablematerial into the textile material of tubular main portion 20, whichheat-settable material is capable of setting to a desired shape uponapplication of heat.

Prosthesis 10 further includes tubular branch 30 defined by elongatetubular branch wall 31, extending laterally from tubular main wall 21 oftubular main portion 20. Tubular branch 30 may extend laterally fromtubular main wall 21 at any angle with respect thereto. Most preferably,tubular branch 30 extends substantially perpendicularly from tubularmain wall 21.

As with tubular main portion 20, tubular branch 30 may also beconstructed of any known textile material. For example, tubular branch30 may be a textile material selected from the group consisting of wovenmaterial, knitted material, braided material, and the like. Preferably,tubular main portion 20 and tubular branch portion 30 are constructed ofsimilar textile material, for instance, woven textile material.

Tubular branch wall 31 includes an elongate tubular extent 32 and aflared tubular extent 34 contiguous therewith. Additionally, tubularbranch 30 includes branch lumen 35 defining a fluid passagewaytherethrough. Tubular branch wall 31 is of a generally constant internaldiameter along the length of elongate tubular extent 32. At flaredtubular extent 34, however, the internal diameter of tubular branch wall31 gradually changes, in that it increases or flares with respect toelongate tubular extent 32.

With reference to FIGS. 3, 4, 6 and 7, tubular branch 30 may include aplurality of elongate tubular extents, as best depicted in FIG. 3, whichshows branch 30 including three distinct elongate tubular extents 32 a,32 b and 32 c. Elongate tubular extents 32 a, 32 b and 32 c arepreferably equally spaced along an axis with respect to tubular mainportion 20. Alternatively, elongate tubular extents 32 a, 32 b and 32 cmay be axially spaced and circumferentially offset with respect totubular main wall 21 of tubular main portion 20, as best depicted inFIGS. 4 and 7.

Prosthesis 10 including a plurality of elongate tubular extents 32 a, 32b and 32 c is particularly useful as an aortic arch vascular graft. Insuch an embodiment, each tubular extent 32 a, 32 b and 32 c includes aflared portion 33 a, 33 b and 33 c which is adjacent and contiguous withflared tubular extent 34 and includes junctures 36 a and 36 b betweentubular extents 32 a, 32 b and 32 c. As such, flared tubular extent 34is contiguous with elongate tubular extents 32 a, 32 b and 32 c.

Elongate tubular extents 32 a, 32 b and 32 c may be of the same lengthas shown in FIG. 3, or may be of different lengths independently, asshown in FIG. 4.

Each of elongate tubular extents 32 a, 32 b and 32 c includes agenerally constant internal diameter along the length thereof, andinclude branch lumens 35 a, 35 b and 35 c, respectively, extendingtherethrough. Elongate tubular extents 32 a, 32 b and 32 c may be of thesame internal diameter, or may be of different internal diametersindependent of one another, as shown in FIG. 4. For example, elongatetubular extents 32 a, 32 b and 32 c may all have the same constantinternal diameter of approximately 8 millimeters. Alternatively,elongate tubular extents 32 a, 32 b and 32 c may each have differentinternal diameters, for example elongate tubular extent 32 a may have aninternal diameter of approximately 10 millimeters, while elongatetubular extents 32 b and 32 c may have an internal diameter ofapproximately 8 millimeters.

In such preferred embodiments where tubular branch 30 includes aplurality of elongate tubular extents 32 a, 32 b and 32 c, the internaldiameter of flared tubular extent 34 gradually changes in a similarmanner as with the embodiment shown in FIG. 2 in that it increases orflares along the length of flared tubular extent 34.

Flared tubular extent 34 of tubular branch 30 is secured to tubular mainwall 21 of tubular main portion 20 along a portion thereof, for example,by sutures 15. As such, a path of fluid communication between main lumen25 of tubular main portion 20 and branch lumen 35 of tubular branch 30is established, thereby providing a passageway for blood flowtherethrough. Since flared tubular extent 34 incorporates a gradualchange in the diameter of tubular branch 32, a smooth and unobstructedpath for blood flow is accomplished at the transition to elongatetubular branch 32. The gradual change in diameter with flared tubularextent 34 provides for a smooth transition from main lumen 25 of tubularmain portion 20 to branch lumen 35 of tubular branch 30, as opposed tothe sharp transition encountered with prior art end-to-side vascularprostheses, as depicted in FIG. 1 and discussed above. Furthermore, inembodiments incorporating a plurality of elongate tubular extents 32 a,32 b and 32 c including branch lumens 35 a, 35 b and 35 c, respectively,extending therethrough, branch lumens 35 a, 35 b and 35 c converge andcontiguously join with flared tubular extent 34 at junctures 36 a and 36b. As such, a path of fluid communication exists between branch lumen 35within flared tubular extent 34 and each of branch lumens 35 a, 35 b and35 c within elongate tubular extents 32 a, 32 b and 32 c. Thus, withflared tubular extent 34 of tubular branch 30 being secured to tubularmain wall 21 of tubular main portion 20 through sutures 15, a smooth andunobstructed path of fluid communication between main lumen 25 and eachof branch lumens 35 a, 35 b and 35 c is established through branch lumen35 within flared tubular extent 34.

FIG. 5 depicts a view of the prior art prosthesis 10′ as in FIG. 1,showing a cutaway portion of tubular main wall 21′ at the location ofsecurement of tubular branches 30 a′, 30 b′ and 30 c′ viewed from withinmain lumen 25′. Such individual suturing directly at the transition frommain lumen 25′ to branch lumens 35 a′, 35 b′ and 35 c′ results inundesirable bulking directly at the point of lumen transition, which canlead to thrombosis at the lumen transition. Furthermore, as is clearlyevident in FIG. 5, individual suturing of tubular branches 30 a′, 30 b′and 30 c′ by way of sutures 15′ results in wall portions 26′ of maintubular wall 21′ extending between the areas of securement of tubularbranches 30 a′, 30 b′ and 30 c′. Such wall portions 26′ result in asharp transition from tubular main lumen 25′ to branch lumens 35 a′, 35b′ and 35 c′. This sharp transition creates turbulence in the path ofblood flow between main lumen 25′ and branch lumens 35 a′, 35 b′ and 35c′, which can result in improper blood flow to the branch lumens 35 a′,35 b′ and 35 c′.

FIG. 6 depicts a cutaway portion of prosthesis 10 according to thepresent invention in a similar manner of FIG. 5, showing tubular mainwall 21 at the location of securement of tubular branch 30, viewed fromwithin main lumen 25. Sutures 15 are provided at a location spaced fromthe transition between main lumen 25 of tubular main portion 20 andbranch lumens 35 a, 35 b and 35 c of tubular branch 30. As such,prosthesis 10 does not include any suturing directly at the transitionbetween main lumen 25 and branch lumens 35 a, 35 b and 35 c, in thatsuch lumen transition is accomplished gradually over the length offlared tubular extent 34. Further, flared portions 33 a, 33 b and 33 cof each tubular branch 32 a, 32 b and 32 c together with junctures 36 aand 36 b therebetween establish a gradual transition region for the pathof blood flow between main lumen 25 and branch lumens 35 a, 35 b and 35c. Thus, undesirable thrombosis at the lumen transition is reduced ascompared with prior art grafts, in that prosthesis 10 of the presentinvention does not incorporate a sharp transition from one lumen toanother and does not include any sutures directly at the transition.

Prosthesis 10 may further include an elongate tubular port 40 extendinglaterally from tubular main wall 21 of tubular main portion 20. Tubularport 40 includes tubular port wall 41 which defines port lumen 45extending therethrough. Tubular port 40 is secured to tubular main wall21 of tubular main portion 20, for example by way of port sutures 16. Assuch, port lumen 45 is in fluid communication with main lumen 25 oftubular main portion 20.

Tubular port 40 is provided as a procedural aid for use during surgicalimplantation procedures. For example, oftentimes it is desirable toaccess main lumen 25 of prosthesis 10 during a surgical procedure fromoutside of the body. Tubular port 40 provides a means for such access.Tubular port 40 is not meant for anastomosis to any part of the body,but is provided for temporary use during a surgical procedure. Aftercompletion of an implant procedure, tubular port 40 is preferablyligated and tied off, for example by way of sutures, to provide acompletely closed main lumen 25.

Preferably, tubular port 40 extends from tubular main wall 21 at alocation remote from tubular branch 30. Most preferably, tubular port 40extends substantially perpendicularly from

tubular main wall 21 at a 90° angle with respect to laterally extendingtubular branch 30, as best depicted in FIG. 7.

Prosthesis 10 is preferably capable of maintaining a blood-tightatmosphere at the time of implantation. In order to control the porosityof prosthesis 10, a natural or synthetic sealant may be incorporatedinto the textile structure, as is known in the art. For example,collagen may be incorporated into the textile structure of prosthesis 10to act as a sealant. Such collagen is typically resorbed by the bodyover time, and is replaced with native tissue, which further serves toanchor prosthesis 10 in place within the body.

Having described the prosthesis of the present invention, itsconstruction and manufacture will now be discussed. As noted, theprosthesis of the present invention is constructed of textile material,such as a woven, knitted or braided material. Such textile materials areparticularly useful in vascular graft applications, in that the textilepattern of the material can be constructed to be very pliable andcapable of permitting sufficient ingrowth of surrounding tissue, whilealso being capable of maintaining a fluid-tight, i.e., blood-tight wallstructure.

The textile prosthesis of the present invention is preferably a wovenmaterial, and can be woven using any known weave pattern, includingsimple weaves, basket weaves, twill weaves, velour weaves and the like,and is most preferably woven using a flat plain tubular weave pattern,preferably with about 100-200 warp yarns per inch per layer and about70-120 fill yarns per inch per layer, more preferably with about 170-190warp yarns per inch per layer and about 86-90 fill yarns per inch perlayer. The wall thickness of the graft may be any conventional usefulthickness, but is preferably no greater than about 1.0 mm, with the mostpreferable wall thickness being from about 0.10 mm to about 0.75 mm.

Any type of textile product can be used as the yarns or fibers of thepresent invention. Of particular usefulness are synthetic materials sucha thermoplastic polymers. Thermoplastic yarns suitable for use in theprostheses of the present invention include, but are not limited to,polyesters, polypropylenes, polyethylenes, polyurethanes,polytetrafluoroethylenes, and mixtures thereof. The yarns may be of themonofilament, multifilament, or spun type.

The yarns used in forming the grafts of the present invention may beflat, twisted or textured, and may have high, low or moderate shrinkageproperties. Additionally, the yarn type and yarn denier can be selectedto meet specific properties for the prosthesis, such as porosity,flexibility and compliance. The yarn denier represents the lineardensity of the yarn (number of grams mass divided by 9,000 meters oflength). Thus, a yarn with a small denier would correspond to a veryfine yarn whereas a yarn with a larger denier, e.g., 1000, wouldcorrespond to a heavy yarn. The yarns used in the prosthesis of thepresent invention preferably have a denier from about 20 to about 1000,more preferably from about 40 to about 300. Preferably, the warp andfill yarns are polyester, and most preferably the warp and fill yarnsare one ply, 50 denier, 48 filament flat polyester.

In preferred embodiments of the present application, prosthesis 10, andin particular tubular main portion 20 and tubular branch 30 areindependently constructed of woven textile material. Woven tubulartextile products are particularly useful in manufacturing vascular graftproducts in that a variety of unique shapes and sizes can now beaccomplished. For example, in U.S. Pat. No. 5,800,114, the disclosure ofwhich is incorporated herein by reference, unique tubular woven textileproducts such as vascular grafts are seamless woven into a variety ofshapes and sizes to manufacture blood-tight conduits. In particular,seamless, tapered, blood-tight tubular-woven textile grafts aredisclosed, including bifurcated and trifurcated structures which aresubstantially blood-tight at the juncture between the bi- andtrifurcations, and therefore do not require any additional stitching orsuturing to maintain a blood-tight wall.

More particularly, it is possible to accomplish disengaging and/orengaging of selected warp yarns to create gradual changes with size,shape or configuration of the graft during weaving of the graft. Suchdisengaging and/or engaging of the warp yarns must be accomplished in agradual transition in order to prevent holes or voids between thecontiguous sections of the woven graft. It is known that a delicatebalance exists between porosity of the graft for proper ingrowth and theneed in many applications for fluid-tight walls. It has been determinedthat a void greater than the diameter of about three warp yarns resultsin a graft with a porosity which is unacceptable as a fluid-tightconduit and may be incapable of sufficiently maintaining blood pressuretherein. Thus, the transition from a graft section of one diameter to agraft section of another diameter, as in the transition from elongatetubular extents 32 a, 32 b and 32 c to flared tubular extent 34, must beaccomplished in fluid-tight applications without creating such voidsbetween the contiguous weave sections which are generally greater thanthe diameter of three warp yarns.

As noted, transition from one diameter to another diameter can beaccomplished by gradually engaging and/or disengaging selected warpyarns from the weave pattern. Such a transition can be effectivelyaccomplished by engaging or disengaging a maximum of three warp yarnsper four successive machine picks for a given weave pattern on each edgeof the graft, as is discussed in more detail in U.S. application Ser.No. 08/653,028, incorporated herein by reference.

Alternatively, transition from one diameter to another diameter can beaccomplished in the fabric by a post-manufacturing technique, such asheat-shaping, shrink-fitting, molding, and the like. In such techniques,the tubular branch 30 is constructed of textile material, for example,by weaving, knitting or braiding. Tubular branch 30 may then be fittedonto a mandrel in a desired shape, such as a flared shape, and may beheat-shrunk to set the fibers of the fabric into the desired flaredshape of the mandrel. Upon removal from the mandrel, tubular branch 30is set to the desired flared shape.

Such unique textile structures are particularly useful as tubular branch30 in the prosthesis of the present invention. For example, atrifurcated tubular structure can be manufactured in a seamless,tubular-woven form, to create a substantially fluid-tight structure.Such structure can then be secured to a separate tubular graft structurein the form of tubular main portion 20 at tubular main wall 21. Thus,prosthesis 10 is produced which incorporates a gradual transitionalchange in diameter from main tubular lumen 25 to branch lumens 35 a, 35b and 35 c, which transition is seamless along the length thereof anddoes not require additional stitching to maintain a fluid-tightconstruction.

Various other modifications to the foregoing disclosed embodiments willnow be evident to those skilled in the art. Thus, the particularlydescribed preferred embodiments are intended to be illustrative and notlimited thereto. The true scope of the invention is set forth in thefollowing claims.

What is claimed is:
 1. An implantable textile prosthesis comprising: afirst woven section comprising an elongate tubular main wall defining afluid passageway therethrough; and a second woven section comprising atubular branch wall defining a fluid passageway therethrough, saidtubular branch wall including an elongate tubular extent and anasymptotically flared tubular extent, asymptotic with respect to saidtubular branch wall, having a first and a second end, said second end ofsaid asymptotically flared tubular extent being contiguous with saidelongate tubular extent, said asymptotically flared tubular extentincluding a weaving pattern having a plurality of warp yarns and fillyarns and incorporating a gradual change in the number of warp yarnswith respect to said fill yarns to provide a seamless and substantiallyfluid-tight transition region along said flared tubular extent; saidfirst end of said asymptotically flared tubular extent being secured tosaid first woven section to provide said tubular branch wall extendinglaterally in a substantially perpendicular fashion from said tubularmain wall, to establish fluid communication between said tubular mainwall and said tubular branch wall and to provide a substantiallynon-turbulent fluid path therethrough.
 2. The prosthesis of claim 1,wherein said gradual change in the number of warp yarns in said weavingpattern is defined by a change of no more than 3 of said warp yarns forevery 2 of said fill yarns to create said substantially fluid-tighttransition.
 3. The prosthesis of claim 1, wherein said woven sectionsare constructed of material selected from the group consisting ofpolyester, polypropylene, polyethylene, polyurethane,polytetrafluoroethylene and mixtures thereof.
 4. The prosthesis of claim1, wherein said tubular main wall is arched.
 5. The prosthesis of claim1, wherein said first end of said asymptotically flared tubular extentis sutured to said first woven section.
 6. The prosthesis of claim 1,wherein said tubular branch wall further includes a plurality ofelongate tubular extents contiguous with said asymptotically flaredtubular extent.
 7. The prosthesis of claim 6, wherein said plurality ofelongate tubular extents are circumferentially offset with respect tosaid tubular main wall.
 8. The prosthesis of claim 6, wherein saidplurality of elongate tubular extents are dimensionally different. 9.The prosthesis of claim 1, further including an elongate tubular portextending laterally from said tubular main wall at a location remotefrom said tubular branch wall.
 10. A method for making an implantabletextile prosthesis comprising: weaving a first section comprising anelongate tubular main wall defining a fluid passageway therethrough; andweaving a second section comprising a tubular branch wall defining afluid passageway therethrough, wherein weaving said tubular branch wallincludes weaving an elongate tubular extent and weaving anasymptotically flared tubular extent, asymptotic with respect to saidtubular branch wall, having a first and a second end, said second end ofsaid asymptotically flared tubular extent being contiguous with saidelongate tubular extent, wherein weaving said asymptotically flaredtubular extent includes weaving a plurality of warp yarns and fill yarnsand incorporating a gradual change in the number of warp yarns withrespect to said fill yarns to provide a seamless and substantiallyfluid-tight transition region along said flared tubular extent; andsecuring said first end of said asymptotically flared tubular extent tosaid first section to provide said tubular branch wall extendinglaterally in a substantially perpendicular fashion from said tubularmain wall, to establish fluid communication between said tubular mainwall and said tubular branch wall and to provide a substantiallynon-turbulent fluid path therethrough.
 11. The method of claim 10,wherein said incorporating said gradual change in the number of warpyarns includes changing no more than 3 of said warp yarns for every 2 ofsaid fill yarns to create said substantially fluid-tight transition. 12.The method of claim 10, further including the step of selecting yarnsfrom the group consisting of polyester yarns, polypropylene yarns,polyethylene yarns, polyurethane yarns, polytetrafluoroethylene yarnsand combinations thereof.
 13. The method of claim 10, wherein saidsecuring said first end of said asymptotically flared tubular extent tosaid first section includes suturing said extends.
 14. The method ofclaim 10, wherein said weaving said elongate tubular extent includesweaving a plurality of elongate tubular extents contiguous with saidasymptotically flared tubular extent.